Gas turbines typically include a plurality of rows of stationary turbine vanes extending radially inward from a casing forming a stator and a plurality of rows of rotatable turbine blades attached to a rotor assembly that rotates relative to the turbine stator. Typically, a turbine rim seal seals the gaps between the turbine stators and turbine rotors to minimize the loss of cooling air from the rotor assembly and hot gas ingestion into a gap or space between the turbine stators and turbine rotors.
During operation from a start up to steady state load operation the position of the rotating turbine rotor relative to the turbine stator changes due to different thermal expansion of the different components and centrifugal forces acting on the rotor. The resulting relative displacement depends on the location of a part on the rotor, respectively on the stator. Consequently, the position of sealing surfaces of a rim seal, respectively a gap of a rim seal changes during the operation of a gas turbine. As a result the leakage of a seal can change during operation. An increase in leakage reduces the gas turbine performance; in particular the power and efficiency can be reduced, and a leakage can have detrimental effect on the gas turbine's emissions. A reduction in the gap width can lead to rubbing between rotor and stator parts and can damage the gas turbine.
From the US2009/0014964 a seal system for an intersection between a turbine stator and a turbine rotor to seal cooling fluids is known. This seal system is formed from a seal base extending from the turbine stator, an arm extending radially outward from the turbine rotor and toward the seal base but terminating short of the seal base thereby creating a gap between the seal base and the arm. The seal system further includes a honeycomb shaped seal attached to the seal base and extending radially inward from the seal base toward the arm wherein the outer sealing surface is nonparallel with a longitudinal axis about which the turbine rotor rotates thereby reducing the distance of the gap with axial movement of the turbine rotor.